Estimate focus limits from lens settings
Use the real focal length, aperture, subject distance, and circle of confusion preset. The model is a thin-lens approximation for planning, not a camera-specific simulator.
Preset CoC is active.
Assumptions
Subject distance is technically measured from the sensor plane, but this page treats entered distance as a practical field estimate. It does not reproduce lens design, effective f-number at high magnification, focus breathing, or manufacturer-specific CoC standards.
Use the result as a shooting-plan reference. It does not replace focus checking, review magnification, or test shots in the field.
Formula
Internal units are millimetres. Hyperfocal distance: H = f² / (N c) + f. Near limit: Hs / (H + (s - f)). Far limit: Hs / (H - (s - f)). If the far denominator is zero or negative, the far limit is shown as infinity.
Nearby photography tools
Print DPI Calculator checks whether image pixels are enough for print size. Aspect Ratio Calculator handles image or frame proportions. Lens and mirror equation covers classroom thin-lens image distance and magnification.
FAQ
What is depth of field?
Depth of field is the distance range in front of and behind the focused subject that appears acceptably sharp under the chosen circle of confusion.
What is hyperfocal distance?
Hyperfocal distance is the focus distance where the far limit reaches infinity for the selected focal length, f-number, and CoC.
Which focal length should I enter?
Enter the real focal length in millimetres, not the 35mm-equivalent value shown for field of view comparisons.
Why is the far limit infinity?
The far limit becomes infinity when the far-limit denominator is zero or negative, meaning the selected focus distance is at or beyond the hyperfocal condition.